Date: Sunday, November 8, 2015
Session Type: ACR Poster Session A
Session Time: 9:00AM-11:00AM
Tuberculosis (TB), a
reportable disease world-wide, is rare in the US (2013 incidence rate [IR]: 3
cases per 100,000 persons)1 and is an event of interest in patients
(pts) receiving biologic (b)DMARDs. Large healthcare claims databases are
useful in assessing rare events, but confirmation of TB in the absence of information
on culture results can be challenging. Typically, an International
Classification of Diseases, Ninth Revision (ICD-9) code is used to identify an
event, although these codes may be limited by varying sensitivity and poor
positive predictive value.2 In a published study by Calderwood et
al., combinations of diagnostic codes, dispensed anti-TB medications and
procedure codes (e.g. chest radiographs or sputum staining for acid-fast
bacteria) detected TB cases with high sensitivity. Dispensing of two or more
anti-TB medications was the most sensitive criterion, with a sensitivity of 89%.3
The present analysis compares TB risk in pts using abatacept or other
bDMARDs via these two methods.
Commercial and Supplemental Medicare databases who initiated treatment with abatacept
or another bDMARD between July 1, 2006 and July 31, 2012 were included in the
analysis. Included pts had at least 180 days of continuous health plan enrollment
prior to and ≥1 day following initiation of the qualifying RA treatment. TB
cases were defined using two methods: 1) at least 1 claim for an ICD-9 code indicating
TB after initiation of a bDMARD and 2) applying the algorithm described by
Calderwood et al.3 IRs (per 1000 person-years) were calculated using
both methods. A Cox regression analysis, adjusted for propensity score and
prior bDMARD use, was conducted to compare the 2 cohorts.
abatacept initiators vs 63 cases among 37,441 initiators of other bDMARDs,
corresponding to an IR (95% CI) of 2.65 (1.66, 4.01) vs 1.99 (1.53, 2.55),
respectively. Using the second method, there were 3 cases of TB among abatacept
initiators vs 5 cases among initiators of other bDMARDs, corresponding to an IR
(95% CI) of 0.36 (0.07, 1.05) vs 0.16 (0.05, 0.37), respectively. The adjusted
hazard ratio (95% CI) comparing abatacept initiators with initiators of other
bDMARDs was 2.38 (0.95, 5.98) using method 1 and 1.00 (0.06, 15.99) using
Conclusion: Although we are unable to determine true positive or
negative cases of TB in the claims-based data, applying the Calderwood
algorithm provided estimates consistent with published rates of TB among pts with
RA.4 These results are also consistent with previous research
demonstrating that TB diagnostic codes alone have poor positive predictive
value. Validated algorithms are important when using claims-based data to
evaluate TB events among pts with RA and in studies assessing the relationship
between TB and treatment for RA.
Disease Control and Prevention. http://www.cdc.gov/tb/statistics/tbcases.htm. Accessed January 2015.
al. Pharmacoepidemiol Drug Saf 2011;20:229–35.
et al. Public Health Rep 2010;125:843–50.
al. Ann Rheum Dis 2014; Published Online First: doi:10.1136/
To cite this abstract in AMA style:Baker N, Suissa S, Kawabata H, Skovron M, Moorthy V, Simon T. Tuberculosis Risk Among Patients with Rheumatoid Arthritis in a United States Claims Database Initiating Abatacept and Other Biologic Disease-Modifying Antirheumatic Drugs: Analyses Using International Classification of Diseases Codes and a Published Claims Algorithm [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/tuberculosis-risk-among-patients-with-rheumatoid-arthritis-in-a-united-states-claims-database-initiating-abatacept-and-other-biologic-disease-modifying-antirheumatic-drugs-analyses-using-internationa/. Accessed September 21, 2019.
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